trying to find out for you - lakenheath has f-15s, mildenhall is refuelling and air support, so it could be big transports from there that you are hearing.
i do remember my dad telling me about the mid-80s libya bombings. he said that from where he was (near bury st edmunds) he heard the planes leaving and returing. bloody loud he said, and they all knew what they were going for.
as a kid i got so used to seeing [and hearing!] all sorts of stuff overhead - jags, gr1s, a-111, a-10, f-14, f-15, f-16. you occaisionally saw awacs and nimrod high up. mainly it was f-4 phantoms though.